In a device of this nature as described in FR-A 857 269, one of the edges of the board is provided with a pair of sheet-retaining rings, and these rings interconnect the two faces of the board in such a manner as to make it possible to pass the sheets from one of the two sides of the board to the other by rotating them through 360.degree. around the rings. The device is reversible, thus making it possible to write on both faces of the sheets, with each face of the board serving as a writing surface if the device is turned over.
A device of this nature has the advantage of making it possible and convenient to write on both the front face and on the rear face of the sheets. However, it suffers from the drawback that, when the device is placed on a support surface, in particular on a table or a desk, the sheets placed under the board deform under gravity and rest against said support surface. The sheets may thus be soiled if the support surface is not completely clean; conversely, the writing on the sheets may be partially transferred onto the support surface and may soil it, in particular if the ink used for writing has not completely dried. Further, the device is awkward to displace since the sheets underneath the board hang vertically therefrom whenever the device is lifted.
A diary of independent sheets, as described in particular in FR-A-2 450 696, comprises a support plate constituting a writing surface on which a block of sheets is removably retained by a ring i.e., which is incomplete (which is not closed). A compartment is provided beneath the support plate for archiving purposes, i.e., for storing sheets which have already been used. This is thus a block of detachable sheets of the calender type which generally has 52 sheets with the days and working hours of each week in the year marked on a front face for noting appointments. Such a device suffers from drawbacks. Firstly, it is difficult to look for sheets which have already been used, since the detached sheets are loose. Secondly, if the support is compact, additional notes concerning the current week are written on the back of the sheet for the preceding week, and this is a source of error when looking through sheets that have been archived. Thirdly, it is difficult to write such notes, since to do so a sheet must be taken out from the compartment and placed on the writing surface.